Toe jacks are used to lift heavy loads that have very low clearances close to the ground. The "toe" is the fork like portion of the jack that has a low profile to get under equipment before moving onto skates or adding shims to level or align equipment.
Hydraulic power allows for great lifting capacity. Loads can be lifted by the toe area or from the upper (head) of the jack. The lifting capacity when lifting at the "toe" is approximately half of the "head" or total lifting capacity.